# License or the Artistic License, as specified in the README file.
#
package B;
-require DynaLoader;
+
+our $VERSION = '1.07';
+
+use XSLoader ();
require Exporter;
-@ISA = qw(Exporter DynaLoader);
-@EXPORT_OK = qw(byteload_fh byteload_string minus_c ppname
+@ISA = qw(Exporter);
+
+# walkoptree_slow comes from B.pm (you are there),
+# walkoptree comes from B.xs
+@EXPORT_OK = qw(minus_c ppname save_BEGINs
class peekop cast_I32 cstring cchar hash threadsv_names
main_root main_start main_cv svref_2object opnumber
- walkoptree walkoptree_slow walkoptree_exec walksymtable
- parents comppadlist sv_undef compile_stats timing_info init_av);
+ amagic_generation perlstring
+ walkoptree_slow walkoptree walkoptree_exec walksymtable
+ parents comppadlist sv_undef compile_stats timing_info
+ begin_av init_av check_av end_av regex_padav dowarn
+ defstash curstash warnhook diehook inc_gv
+ );
+
sub OPf_KIDS ();
use strict;
@B::SV::ISA = 'B::OBJECT';
@B::PVIV::ISA = qw(B::PV B::IV);
@B::PVNV::ISA = qw(B::PV B::NV);
@B::PVMG::ISA = 'B::PVNV';
-@B::PVLV::ISA = 'B::PVMG';
+# Change in the inheritance hierarchy post 5.8
+@B::PVLV::ISA = $] > 5.009 ? 'B::GV' : 'B::PVMG';
@B::BM::ISA = 'B::PVMG';
@B::AV::ISA = 'B::PVMG';
@B::GV::ISA = 'B::PVMG';
@B::UNOP::ISA = 'B::OP';
@B::BINOP::ISA = 'B::UNOP';
@B::LOGOP::ISA = 'B::UNOP';
-@B::CONDOP::ISA = 'B::UNOP';
@B::LISTOP::ISA = 'B::BINOP';
@B::SVOP::ISA = 'B::OP';
-@B::GVOP::ISA = 'B::OP';
+@B::PADOP::ISA = 'B::OP';
@B::PVOP::ISA = 'B::OP';
-@B::CVOP::ISA = 'B::OP';
@B::LOOP::ISA = 'B::LISTOP';
@B::PMOP::ISA = 'B::LISTOP';
@B::COP::ISA = 'B::OP';
package B::OBJECT;
}
+sub B::GV::SAFENAME {
+ my $name = (shift())->NAME;
+
+ # The regex below corresponds to the isCONTROLVAR macro
+ # from toke.c
+
+ $name =~ s/^([\cA-\cZ\c\\c[\c]\c?\c_\c^])/"^".
+ chr( utf8::unicode_to_native( 64 ^ ord($1) ))/e;
+
+ # When we say unicode_to_native we really mean ascii_to_native,
+ # which matters iff this is a non-ASCII platform (EBCDIC).
+
+ return $name;
+}
+
+sub B::IV::int_value {
+ my ($self) = @_;
+ return (($self->FLAGS() & SVf_IVisUV()) ? $self->UVX : $self->IV);
+}
+
+sub B::NULL::as_string() {""}
+sub B::IV::as_string() {goto &B::IV::int_value}
+sub B::PV::as_string() {goto &B::PV::PV}
+
my $debug;
my $op_count = 0;
my @parents = ();
# For debugging
sub peekop {
my $op = shift;
- return sprintf("%s (0x%x) %s", class($op), $$op, $op->ppaddr);
+ return sprintf("%s (0x%x) %s", class($op), $$op, $op->name);
}
sub walkoptree_slow {
}
shift @parents;
}
+ if (class($op) eq 'PMOP' && $op->pmreplroot && ${$op->pmreplroot}) {
+ unshift(@parents, $op);
+ walkoptree_slow($op->pmreplroot, $method, $level + 1);
+ shift @parents;
+ }
}
sub compile_stats {
}
my %symtable;
+
+sub clearsym {
+ %symtable = ();
+}
+
sub savesym {
my ($obj, $value) = @_;
# warn(sprintf("savesym: sym_%x => %s\n", $$obj, $value)); # debug
sub walkoptree_exec {
my ($op, $method, $level) = @_;
+ $level ||= 0;
my ($sym, $ppname);
my $prefix = " " x $level;
for (; $$op; $op = $op->next) {
}
savesym($op, sprintf("%s (0x%lx)", class($op), $$op));
$op->$method($level);
- $ppname = $op->ppaddr;
- if ($ppname =~ /^pp_(or|and|mapwhile|grepwhile|entertry)$/) {
+ $ppname = $op->name;
+ if ($ppname =~
+ /^(d?or(assign)?|and(assign)?|mapwhile|grepwhile|entertry|range|cond_expr)$/)
+ {
print $prefix, uc($1), " => {\n";
walkoptree_exec($op->other, $method, $level + 1);
print $prefix, "}\n";
- } elsif ($ppname eq "pp_match" || $ppname eq "pp_subst") {
+ } elsif ($ppname eq "match" || $ppname eq "subst") {
my $pmreplstart = $op->pmreplstart;
if ($$pmreplstart) {
print $prefix, "PMREPLSTART => {\n";
walkoptree_exec($pmreplstart, $method, $level + 1);
print $prefix, "}\n";
}
- } elsif ($ppname eq "pp_substcont") {
+ } elsif ($ppname eq "substcont") {
print $prefix, "SUBSTCONT => {\n";
walkoptree_exec($op->other->pmreplstart, $method, $level + 1);
print $prefix, "}\n";
$op = $op->other;
- } elsif ($ppname eq "pp_cond_expr") {
- # pp_cond_expr never returns op_next
- print $prefix, "TRUE => {\n";
- walkoptree_exec($op->true, $method, $level + 1);
- print $prefix, "}\n";
- $op = $op->false;
- redo;
- } elsif ($ppname eq "pp_range") {
- print $prefix, "TRUE => {\n";
- walkoptree_exec($op->true, $method, $level + 1);
- print $prefix, "}\n", $prefix, "FALSE => {\n";
- walkoptree_exec($op->false, $method, $level + 1);
- print $prefix, "}\n";
- } elsif ($ppname eq "pp_enterloop") {
+ } elsif ($ppname eq "enterloop") {
print $prefix, "REDO => {\n";
walkoptree_exec($op->redoop, $method, $level + 1);
print $prefix, "}\n", $prefix, "NEXT => {\n";
print $prefix, "}\n", $prefix, "LAST => {\n";
walkoptree_exec($op->lastop, $method, $level + 1);
print $prefix, "}\n";
- } elsif ($ppname eq "pp_subst") {
+ } elsif ($ppname eq "subst") {
my $replstart = $op->pmreplstart;
if ($$replstart) {
print $prefix, "SUBST => {\n";
my ($symref, $method, $recurse, $prefix) = @_;
my $sym;
my $ref;
- no strict 'vars';
- local(*glob);
+ my $fullname;
+ no strict 'refs';
$prefix = '' unless defined $prefix;
while (($sym, $ref) = each %$symref) {
- *glob = $ref;
+ $fullname = "*main::".$prefix.$sym;
if ($sym =~ /::$/) {
$sym = $prefix . $sym;
- if ($sym ne "main::" && &$recurse($sym)) {
- walksymtable(\%glob, $method, $recurse, $sym);
+ if ($sym ne "main::" && $sym ne "<none>::" && &$recurse($sym)) {
+ walksymtable(\%$fullname, $method, $recurse, $sym);
}
} else {
- svref_2object(\*glob)->EGV->$method();
+ svref_2object(\*$fullname)->$method();
}
}
}
package B::Section;
my $output_fh;
my %sections;
-
+
sub new {
my ($class, $section, $symtable, $default) = @_;
$output_fh ||= FileHandle->new_tmpfile;
$sections{$section} = $obj;
return $obj;
}
-
+
sub get {
my ($class, $section) = @_;
return $sections{$section};
my $section = shift;
return $section->[2];
}
-
+
sub default {
my $section = shift;
return $section->[3];
}
-
+
sub output {
my ($section, $fh, $format) = @_;
my $name = $section->name;
}
}
-bootstrap B;
+XSLoader::load 'B';
1;
things as SVs, OPs and the internal symbol table and syntax tree
of a program.
+=head1 OVERVIEW
+
+The C<B> module contains a set of utility functions for querying the
+current state of the Perl interpreter; typically these functions
+return objects from the B::SV and B::OP classes, or their derived
+classes. These classes in turn define methods for querying the
+resulting objects about their own internal state.
+
+=head1 Utility Functions
+
+The C<B> module exports a variety of functions: some are simple
+utility functions, others provide a Perl program with a way to
+get an initial "handle" on an internal object.
+
+=head2 Functions Returning C<B::SV>, C<B::AV>, C<B::HV>, and C<B::CV> objects
+
+For descriptions of the class hierachy of these objects and the
+methods that can be called on them, see below, L<"OVERVIEW OF
+CLASSES"> and L<"SV-RELATED CLASSES">.
+
+=over 4
+
+=item sv_undef
+
+Returns the SV object corresponding to the C variable C<sv_undef>.
+
+=item sv_yes
+
+Returns the SV object corresponding to the C variable C<sv_yes>.
+
+=item sv_no
+
+Returns the SV object corresponding to the C variable C<sv_no>.
+
+=item svref_2object(SVREF)
+
+Takes a reference to any Perl value, and turns the referred-to value
+into an object in the appropriate B::OP-derived or B::SV-derived
+class. Apart from functions such as C<main_root>, this is the primary
+way to get an initial "handle" on an internal perl data structure
+which can then be followed with the other access methods.
+
+=item amagic_generation
+
+Returns the SV object corresponding to the C variable C<amagic_generation>.
+
+=item init_av
+
+Returns the AV object (i.e. in class B::AV) representing INIT blocks.
+
+=item check_av
+
+Returns the AV object (i.e. in class B::AV) representing CHECK blocks.
+
+=item begin_av
+
+Returns the AV object (i.e. in class B::AV) representing BEGIN blocks.
+
+=item end_av
+
+Returns the AV object (i.e. in class B::AV) representing END blocks.
+
+=item comppadlist
+
+Returns the AV object (i.e. in class B::AV) of the global comppadlist.
+
+=item regex_padav
+
+Only when perl was compiled with ithreads.
+
+=item main_cv
+
+Return the (faked) CV corresponding to the main part of the Perl
+program.
+
+=back
+
+=head2 Functions for Examining the Symbol Table
+
+=over 4
+
+=item walksymtable(SYMREF, METHOD, RECURSE, PREFIX)
+
+Walk the symbol table starting at SYMREF and call METHOD on each
+symbol (a B::GV object) visited. When the walk reaches package
+symbols (such as "Foo::") it invokes RECURSE, passing in the symbol
+name, and only recurses into the package if that sub returns true.
+
+PREFIX is the name of the SYMREF you're walking.
+
+For example:
+
+ # Walk CGI's symbol table calling print_subs on each symbol.
+ # Recurse only into CGI::Util::
+ walksymtable(\%CGI::, 'print_subs', sub { $_[0] eq 'CGI::Util::' },
+ 'CGI::');
+
+print_subs() is a B::GV method you have declared. Also see L<"B::GV
+Methods">, below.
+
+=back
+
+=head2 Functions Returning C<B::OP> objects or for walking op trees
+
+For descriptions of the class hierachy of these objects and the
+methods that can be called on them, see below, L<"OVERVIEW OF
+CLASSES"> and L<"OP-RELATED CLASSES">.
+
+=over 4
+
+=item main_root
+
+Returns the root op (i.e. an object in the appropriate B::OP-derived
+class) of the main part of the Perl program.
+
+=item main_start
+
+Returns the starting op of the main part of the Perl program.
+
+=item walkoptree(OP, METHOD)
+
+Does a tree-walk of the syntax tree based at OP and calls METHOD on
+each op it visits. Each node is visited before its children. If
+C<walkoptree_debug> (see below) has been called to turn debugging on then
+the method C<walkoptree_debug> is called on each op before METHOD is
+called.
+
+=item walkoptree_debug(DEBUG)
+
+Returns the current debugging flag for C<walkoptree>. If the optional
+DEBUG argument is non-zero, it sets the debugging flag to that. See
+the description of C<walkoptree> above for what the debugging flag
+does.
+
+=back
+
+=head2 Miscellaneous Utility Functions
+
+=over 4
+
+=item ppname(OPNUM)
+
+Return the PP function name (e.g. "pp_add") of op number OPNUM.
+
+=item hash(STR)
+
+Returns a string in the form "0x..." representing the value of the
+internal hash function used by perl on string STR.
+
+=item cast_I32(I)
+
+Casts I to the internal I32 type used by that perl.
+
+=item minus_c
+
+Does the equivalent of the C<-c> command-line option. Obviously, this
+is only useful in a BEGIN block or else the flag is set too late.
+
+=item cstring(STR)
+
+Returns a double-quote-surrounded escaped version of STR which can
+be used as a string in C source code.
+
+=item perlstring(STR)
+
+Returns a double-quote-surrounded escaped version of STR which can
+be used as a string in Perl source code.
+
+=item class(OBJ)
+
+Returns the class of an object without the part of the classname
+preceding the first C<"::">. This is used to turn C<"B::UNOP"> into
+C<"UNOP"> for example.
+
+=item threadsv_names
+
+In a perl compiled for threads, this returns a list of the special
+per-thread threadsv variables.
+
+=back
+
+
+
+
=head1 OVERVIEW OF CLASSES
The C structures used by Perl's internals to hold SV and OP
class hierarchy and the C<B> module gives access to them via a true
object hierarchy. Structure fields which point to other objects
(whether types of SV or types of OP) are represented by the C<B>
-module as Perl objects of the appropriate class. The bulk of the C<B>
-module is the methods for accessing fields of these structures. Note
-that all access is read-only: you cannot modify the internals by
+module as Perl objects of the appropriate class.
+
+The bulk of the C<B> module is the methods for accessing fields of
+these structures.
+
+Note that all access is read-only. You cannot modify the internals by
using this module.
=head2 SV-RELATED CLASSES
B::IV, B::NV, B::RV, B::PV, B::PVIV, B::PVNV, B::PVMG, B::BM, B::PVLV,
B::AV, B::HV, B::CV, B::GV, B::FM, B::IO. These classes correspond in
the obvious way to the underlying C structures of similar names. The
-inheritance hierarchy mimics the underlying C "inheritance". Access
-methods correspond to the underlying C macros for field access,
+inheritance hierarchy mimics the underlying C "inheritance". For 5.9 and
+later this is:
+
+ B::SV
+ |
+ +--------------+----------------------+
+ | | |
+ B::PV B::IV B::RV
+ | \ / \
+ | \ / \
+ | B::PVIV B::NV
+ \ /
+ \____ __/
+ \ /
+ B::PVNV
+ |
+ |
+ B::PVMG
+ |
+ +-----+----+------+-----+-----+
+ | | | | | |
+ B::BM B::AV B::GV B::HV B::CV B::IO
+ | |
+ B::PVLV |
+ B::FM
+
+
+For 5.8 and earlier, PVLV is a direct subclass of PVMG, so the base of this
+diagram is
+
+ |
+ B::PVMG
+ |
+ +------+-----+----+------+-----+-----+
+ | | | | | | |
+ B::PVLV B::BM B::AV B::GV B::HV B::CV B::IO
+ |
+ |
+ B::FM
+
+
+Access methods correspond to the underlying C macros for field access,
usually with the leading "class indication" prefix removed (Sv, Av,
Hv, ...). The leading prefix is only left in cases where its removal
would cause a clash in method name. For example, C<GvREFCNT> stays
as-is since its abbreviation would clash with the "superclass" method
C<REFCNT> (corresponding to the C function C<SvREFCNT>).
-=head2 B::SV METHODS
+=head2 B::SV Methods
=over 4
=item FLAGS
+=item object_2svref
+
+Returns a reference to the regular scalar corresponding to this
+B::SV object. In other words, this method is the inverse operation
+to the svref_2object() subroutine. This scalar and other data it points
+at should be considered read-only: modifying them is neither safe nor
+guaranteed to have a sensible effect.
+
=back
-=head2 B::IV METHODS
+=head2 B::IV Methods
=over 4
=item IV
+Returns the value of the IV, I<interpreted as
+a signed integer>. This will be misleading
+if C<FLAGS & SVf_IVisUV>. Perhaps you want the
+C<int_value> method instead?
+
=item IVX
+=item UVX
+
+=item int_value
+
+This method returns the value of the IV as an integer.
+It differs from C<IV> in that it returns the correct
+value regardless of whether it's stored signed or
+unsigned.
+
=item needs64bits
=item packiv
=back
-=head2 B::NV METHODS
+=head2 B::NV Methods
=over 4
=back
-=head2 B::RV METHODS
+=head2 B::RV Methods
=over 4
=back
-=head2 B::PV METHODS
+=head2 B::PV Methods
=over 4
=item PV
+This method is the one you usually want. It constructs a
+string using the length and offset information in the struct:
+for ordinary scalars it will return the string that you'd see
+from Perl, even if it contains null characters.
+
+=item RV
+
+Same as B::RV::RV, except that it will die() if the PV isn't
+a reference.
+
+=item PVX
+
+This method is less often useful. It assumes that the string
+stored in the struct is null-terminated, and disregards the
+length information.
+
+It is the appropriate method to use if you need to get the name
+of a lexical variable from a padname array. Lexical variable names
+are always stored with a null terminator, and the length field
+(SvCUR) is overloaded for other purposes and can't be relied on here.
+
=back
-=head2 B::PVMG METHODS
+=head2 B::PVMG Methods
=over 4
=back
-=head2 B::MAGIC METHODS
+=head2 B::MAGIC Methods
=over 4
=item MOREMAGIC
+=item precomp
+
+Only valid on r-magic, returns the string that generated the regexp.
+
=item PRIVATE
=item TYPE
=item OBJ
+Will die() if called on r-magic.
+
=item PTR
+=item REGEX
+
+Only valid on r-magic, returns the integer value of the REGEX stored
+in the MAGIC.
+
=back
-=head2 B::PVLV METHODS
+=head2 B::PVLV Methods
=over 4
=back
-=head2 B::BM METHODS
+=head2 B::BM Methods
=over 4
=back
-=head2 B::GV METHODS
+=head2 B::GV Methods
=over 4
+=item is_empty
+
+This method returns TRUE if the GP field of the GV is NULL.
+
=item NAME
+=item SAFENAME
+
+This method returns the name of the glob, but if the first
+character of the name is a control character, then it converts
+it to ^X first, so that *^G would return "^G" rather than "\cG".
+
+It's useful if you want to print out the name of a variable.
+If you restrict yourself to globs which exist at compile-time
+then the result ought to be unambiguous, because code like
+C<${"^G"} = 1> is compiled as two ops - a constant string and
+a dereference (rv2gv) - so that the glob is created at runtime.
+
+If you're working with globs at runtime, and need to disambiguate
+*^G from *{"^G"}, then you should use the raw NAME method.
+
=item STASH
=item SV
=item LINE
+=item FILE
+
=item FILEGV
=item GvREFCNT
=back
-=head2 B::IO METHODS
+=head2 B::IO Methods
=over 4
=item IoFLAGS
+=item IsSTD
+
+Takes one arguments ( 'stdin' | 'stdout' | 'stderr' ) and returns true
+if the IoIFP of the object is equal to the handle whose name was
+passed as argument ( i.e. $io->IsSTD('stderr') is true if
+IoIFP($io) == PerlIO_stdin() ).
+
=back
-=head2 B::AV METHODS
+=head2 B::AV Methods
=over 4
=item ARRAY
+=item ARRAYelt
+
+Like C<ARRAY>, but takes an index as an argument to get only one element,
+rather than a list of all of them.
+
=item AvFLAGS
=back
-=head2 B::CV METHODS
+=head2 B::CV Methods
=over 4
=item GV
-=item FILEGV
+=item FILE
=item DEPTH
=item OUTSIDE
+=item OUTSIDE_SEQ
+
=item XSUB
=item XSUBANY
+For constant subroutines, returns the constant SV returned by the subroutine.
+
=item CvFLAGS
+=item const_sv
+
=back
-=head2 B::HV METHODS
+=head2 B::HV Methods
=over 4
=head2 OP-RELATED CLASSES
-B::OP, B::UNOP, B::BINOP, B::LOGOP, B::CONDOP, B::LISTOP, B::PMOP,
-B::SVOP, B::GVOP, B::PVOP, B::CVOP, B::LOOP, B::COP.
-These classes correspond in
-the obvious way to the underlying C structures of similar names. The
-inheritance hierarchy mimics the underlying C "inheritance". Access
-methods correspond to the underlying C structre field names, with the
-leading "class indication" prefix removed (op_).
+C<B::OP>, C<B::UNOP>, C<B::BINOP>, C<B::LOGOP>, C<B::LISTOP>, C<B::PMOP>,
+C<B::SVOP>, C<B::PADOP>, C<B::PVOP>, C<B::LOOP>, C<B::COP>.
+
+These classes correspond in the obvious way to the underlying C
+structures of similar names. The inheritance hierarchy mimics the
+underlying C "inheritance":
-=head2 B::OP METHODS
+ B::OP
+ |
+ +---------------+--------+--------+
+ | | | |
+ B::UNOP B::SVOP B::PADOP B::COP
+ ,' `-.
+ / `--.
+ B::BINOP B::LOGOP
+ |
+ |
+ B::LISTOP
+ ,' `.
+ / \
+ B::LOOP B::PMOP
+
+Access methods correspond to the underlying C structre field names,
+with the leading "class indication" prefix (C<"op_">) removed.
+
+=head2 B::OP Methods
+
+These methods get the values of similarly named fields within the OP
+data structure. See top of C<op.h> for more info.
=over 4
=item sibling
+=item name
+
+This returns the op name as a string (e.g. "add", "rv2av").
+
=item ppaddr
-This returns the function name as a string (e.g. pp_add, pp_rv2av).
+This returns the function name as a string (e.g. "PL_ppaddr[OP_ADD]",
+"PL_ppaddr[OP_RV2AV]").
=item desc
=item type
-=item seq
+=item opt
+
+=item static
=item flags
=item private
+=item spare
+
=back
=head2 B::UNOP METHOD
=back
-=head2 B::CONDOP METHODS
-
-=over 4
-
-=item true
-
-=item false
-
-=back
-
=head2 B::LISTOP METHOD
=over 4
=back
-=head2 B::PMOP METHODS
+=head2 B::PMOP Methods
=over 4
=item pmflags
+=item pmdynflags
+
=item pmpermflags
=item precomp
+=item pmoffset
+
+Only when perl was compiled with ithreads.
+
=back
=head2 B::SVOP METHOD
=item sv
+=item gv
+
=back
-=head2 B::GVOP METHOD
+=head2 B::PADOP METHOD
=over 4
-=item gv
+=item padix
=back
=back
-=head2 B::LOOP METHODS
+=head2 B::LOOP Methods
=over 4
=back
-=head2 B::COP METHODS
+=head2 B::COP Methods
=over 4
=item stash
-=item filegv
+=item stashpv
+
+=item file
=item cop_seq
=item line
-=back
-
-=head1 FUNCTIONS EXPORTED BY C<B>
-
-The C<B> module exports a variety of functions: some are simple
-utility functions, others provide a Perl program with a way to
-get an initial "handle" on an internal object.
-
-=over 4
-
-=item main_cv
-
-Return the (faked) CV corresponding to the main part of the Perl
-program.
-
-=item init_av
-
-Returns the AV object (i.e. in class B::AV) representing INIT blocks.
-
-=item main_root
-
-Returns the root op (i.e. an object in the appropriate B::OP-derived
-class) of the main part of the Perl program.
-
-=item main_start
-
-Returns the starting op of the main part of the Perl program.
-
-=item comppadlist
-
-Returns the AV object (i.e. in class B::AV) of the global comppadlist.
-
-=item sv_undef
-
-Returns the SV object corresponding to the C variable C<sv_undef>.
-
-=item sv_yes
-
-Returns the SV object corresponding to the C variable C<sv_yes>.
+=item warnings
-=item sv_no
-
-Returns the SV object corresponding to the C variable C<sv_no>.
-
-=item walkoptree(OP, METHOD)
-
-Does a tree-walk of the syntax tree based at OP and calls METHOD on
-each op it visits. Each node is visited before its children. If
-C<walkoptree_debug> (q.v.) has been called to turn debugging on then
-the method C<walkoptree_debug> is called on each op before METHOD is
-called.
-
-=item walkoptree_debug(DEBUG)
-
-Returns the current debugging flag for C<walkoptree>. If the optional
-DEBUG argument is non-zero, it sets the debugging flag to that. See
-the description of C<walkoptree> above for what the debugging flag
-does.
-
-=item walksymtable(SYMREF, METHOD, RECURSE)
-
-Walk the symbol table starting at SYMREF and call METHOD on each
-symbol visited. When the walk reached package symbols "Foo::" it
-invokes RECURSE and only recurses into the package if that sub
-returns true.
-
-=item svref_2object(SV)
-
-Takes any Perl variable and turns it into an object in the
-appropriate B::OP-derived or B::SV-derived class. Apart from functions
-such as C<main_root>, this is the primary way to get an initial
-"handle" on a internal perl data structure which can then be followed
-with the other access methods.
-
-=item ppname(OPNUM)
-
-Return the PP function name (e.g. "pp_add") of op number OPNUM.
-
-=item hash(STR)
-
-Returns a string in the form "0x..." representing the value of the
-internal hash function used by perl on string STR.
-
-=item cast_I32(I)
-
-Casts I to the internal I32 type used by that perl.
-
-
-=item minus_c
-
-Does the equivalent of the C<-c> command-line option. Obviously, this
-is only useful in a BEGIN block or else the flag is set too late.
-
-
-=item cstring(STR)
-
-Returns a double-quote-surrounded escaped version of STR which can
-be used as a string in C source code.
-
-=item class(OBJ)
-
-Returns the class of an object without the part of the classname
-preceding the first "::". This is used to turn "B::UNOP" into
-"UNOP" for example.
-
-=item threadsv_names
-
-In a perl compiled for threads, this returns a list of the special
-per-thread threadsv variables.
-
-=item byteload_fh(FILEHANDLE)
-
-Load the contents of FILEHANDLE as bytecode. See documentation for
-the B<Bytecode> module in F<B::Backend> for how to generate bytecode.
+=item io
=back
+
=head1 AUTHOR
Malcolm Beattie, C<mbeattie@sable.ox.ac.uk>